The "Journey" of Microplastics across the Marine Food Web in China's Largest Fishing Ground

Microplastics in marine environments are becoming a hot topic since they can be transferred through the marine food web and may finally be consumed by humans. Here, we investigate the distribution characteristics of microplastics in marine organisms at different trophic levels through their digestive tracts (entire organisms for zooplankton and zoobenthos). A total of 124 fish and 22 crustaceans from 10 fish and 3 crustacean species, as well as a few zooplankton and zoobenthos, were captured from the Zhoushan fishing ground, i.e., China's largest ocean fishing ground. The abundance of microplastics ranged from 0.74 +/- 1.29 to 4.71 +/- 2.19 items per sample in fish species and from 0.83 +/- 1.07 to 1.00 +/- 0.93 items per sample in crustacean species. Among the detected microplastics, fiber was the most dominant type (i.e., 67%), transparent microplastics were the most frequently detected (i.e., 49%), and the majority of the microplastics were identified as natural particles (cellulose). The abundance of microplastics was positively correlated with the trophic level (correlation coefficient = 0.717; p < 0.05). Our results show that microplastics are widespread in the marine organisms of the Zhoushan fishing ground, and they might accumulate in marine organisms at higher trophic levels of the marine food chain.